container mount success, but directorys are not the same - docker

Question

I create a container with the following command. Docker inspect shows the mounts are success.
But actually the contents in the directories in host and container are not the same.
I have tried to mount /l3/mysql/conf2 to /etc/mysql, but it doesn't work too.
environment:
Lubuntu 22.04
Docker version 20.10.15, build fd82621
docker image: mysql:5.7
docker pull mysql:5.7
docker run -d -p 3306:3306 --privileged=true
-v /l3/mysql/log:/var/log/mysql
-v /l3/mysql/data:/var/lib/mysql
-v /l3/mysql/conf:/etc/mysql/conf.d
-e MYSQL_ROOT_PASSWORD=123456
--name=mysql
mysql:5.7
# directories are created in host, but all of them are empty
cd /l3/mysql/conf
ls
# but the Mounts are created
docker inspect my mysql
<<'END'
"Mounts": [
{
"Type": "bind",
"Source": "/l3/mysql/conf",
"Destination": "/ect/mysql/conf.d",
"Mode": "",
"RW": true,
"Propagation": "rprivate"
},
{
"Type": "bind",
"Source": "/l3/mysql/data",
"Destination": "/var/lib/mysql",
"Mode": "",
"RW": true,
"Propagation": "rprivate"
},
{
"Type": "bind",
"Source": "/l3/mysql/log",
"Destination": "/var/log/mysql",
"Mode": "",
"RW": true,
"Propagation": "rprivate"
}
],
END
# in the container, there are three config files
root#380a7767bae4:/etc/mysql/conf.d# ls
docker.cnf mysql.cnf mysqldump.cnf
When I create a new file test.txt in the host /l3/mysql/conf/, there is no test.txt in /etc/mysql/mysql.conf.d
root#lezhang-Lubuntu:/l3/mysql/conf# ls
test.txt
root#380a7767bae4:/etc/mysql/conf.d# ls
docker.cnf mysql.cnf mysqldump.cnf
Thanks in advance.